Modulating system



Dec. 8, 1942. R. 0. W155 MODULATING SYSTEM Filed May 13, 1941 2 Sheets-Sheet 1 FIG. 2

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lNl ENTOR R0. WISE EV A r TOPNEV Patented Dec. 8, 1942 UNiTED STATES PATENT OFFICE;

MODULATING SYSTEM Raymond 0. Wise, Short Hills, N. 3., assignor to Bell Telephone Laboratories, Incorporated, New York, N. Y., a corporation of New York Application May 13, 1941, Serial No. 393,167

This invention relates to frequency changers 4 Claims.

that the input and output circuits contain waves of different frequencies. High efliciency of energy transfer is attainable by providing a suitable coupling of variable nature between the wave sources and the load. Such coupling effectively regulates the frequency change and controls the amplitude of the output waves in acco dance with variations of certain input wav This invention contemplates a coupling to accomplish the frequency change with minimum loss of energy so as to promote high efficiency.

The main object of the invention is to provide frequency changing apparatus which performs a change in frequency with economy.

- In a specific embodiment, the invention comprises a coupling bridge network embodying an inductance in each of two first adjacent arms and rectifying means in each of two other adjacent arms. Additional inductances coupled to the network inductances serve to connect effectively the bridge network to the sources of alternating current waves, or the load circuit.

The invention will be more readily understood from the following description taken .together with the accompanying drawings, in which:

Fig. l is a schematic circuit showing a coupling network arranged to operate as a frequency changer in accordance with one embodiment of the invention; and

Figs. 2 through 16 are schematic circuits illustrating additional coupling networks 31!".- ranged to operate as frequencychangers in accordance with other embodiments of the inven- In the following description, the same referonce numerals are utilized to identify the same elements appearing in the several figures of the drawings. I

Fig. 1 shows a modulating system in which a Wheatstone bridge network embodies nonlinear rectifiers 26 and 21 which have a common terminal 28 and are so poled that each is conductive toward this common terminal, as indicated by the arrowheads in the schematic representation, and split transformer windings M and 3B which have a common terminal 3|, both terminals 28 and 3| constituting the horizontal diagonal of the bridge network. Rectifier 25 and winding 29 have a common terminal 32, and rectifier 2i and winding 30 have a common terminal 33, both terminals 32 and 33 constituting the vertal diagonal of the bridge network. Across the vertial terminals 32 and 33 is connected a load circuit 34. A carrier wave generator 35 is applied between the horizontal terminals 28 and 3|. The pairs of terminals 28 and 3t and 32 and 33 are conjugately related. the carrier source and load circuit appearing in the respective conjugate branches. Split transformer windings 29 and 30 and 36 and 3'! couple a signal source 38 to thebridge network 25.

The operation of the bridge network 25 of Fig.

l is well known, and briefly comprises applying a signaling voltage across the vertical terminals 32 and 33 and, at the same time, impressing a carrier voltage across the horizontal terminals 28 and 3!. These voltages together with the non-linear resistance characteristic of the rectifiers 26 and 21 produce a modulation action whereby both the carrier and. signaling currents are combined in the well-known manner-to effect a signal modulated carrier wave. This is most efficiently accomplished when the rectifiers and transformer windings comprising the arms of the bridge network are balanced to a relatively high degree of precision in both the conductive and non-conductive directions. The transformer windings 2a and 3t and 36 and 31 prevent effectively direct transmission from the signaling source 38 to the bridge network 25. ,Fig. 2 is similar to Fig. 1 except the carrier generator 35 and signal source 33 are interchanged. The transformer windings 29 and 36 and 3t and ti prevent effectively direct transmission between the carrier generator 35 and the bridge network 25.

Fig. 3 is similar to Fig. 2 except the load circuit 3% is applied across the horizontal ter-' minals 28 and 38 in shunt of the signal source 38.

Fig. 4 is similar to Fig. 1 except the carrier generator 35 and signal source it in series are efiectively coupled to the network 25 by the transformer windings 29 and 3d and 3t and 3i, and the load circuit 3% is directly connected between the horizontal terminals 28 and 3|. The transformer windings 29 and 38 and 38 and 31 prevent efiiectively direct transmission between both the carrier generator 35 and signaling source 38 and the network 25.

- 38 and 36 and 31 prevent effectively direct trans- -mission between the bridge network 25 and the load circuit 34.

Fig. 7 is similar to Fig. 1 except rectifiers 85 and 48 shunt the respective rectifiers 28 and 21 and are poled in a direction individually opposite thereto. In Fig. 7 the conductive direction of one rectifier of each pair of rectifiers in parallel in each network arm is substantially coincident with the non-conductive direction of the other rectifier of the same pair. Thus, when the rectifier 28 is conductive, the rectifier 45 is non-conductive and vice versa; and whenv the rectifier 21 is conductive, the rectifier 48 is nonconductive, and vice versa.

Fig. 8 is similar to Fig. 3 except rectifiers and 52 shunt the respective rectifiers 28 and 21 and are poled in directions individually opposite thereto in a manner identical with the respectively corresponding rectifiers 45 and 98 of Fig. 7.

Fig, 9 is similar to Fig. 1 except the rectifiers 41 and 48 are poled in the same direct-ion with respect to the common terminal 28. Hence. the rectifier 41 is poled in a direction away from the common terminal 28 and rectifier 38 is poled in a direction toward the common terminal 28.

Fig. 10 is similar to Fig. 3 except the non-linear rectifiers 89 and 58 are poled in the same direcbodying rectifiers 88, 81, 88 and 89. Rectifiers 88 and 81 are poled in a direction toward common terminal 11; and rectifiers 88 and 89 are poled in a. direction toward common terminal 18. Across the vertical terminals 13 and 14 is a split transformer winding 15 whose component wind ings are arranged in a series-aiding relation; and

:35 and signaling source 38 in series to the split winding 15 and thereby to the vertical diagonal of the network 18. A split transformer winding 8| couples the load circuit 34 to the split winding 18 and thereby to the horizontal diagonal of the network 18. The rectifiers of the network 18 and the split windings 15 and 18 connecting opposite diagonals thereof are balanced to a relatively high degree of precision in both tion with respect to the common terminal 28..

Thus, the rectifier 49 is poled in a direction away 'from the common terminal 28 and the rectifier 58 is poled in a direction toward the common terminal 28.

Fig. 11 is similar to Fig. 10 except the signaling source 38 and carrier generator 35 are interchanged. 1

Fig. 12 shows a bridge network 55 embodying rectifiers 58, 51, 58 and 59 each of which includes-in series an inductance 68. Rectifiers 58 and 51 are poled in a direction toward a common terminal 8|; and rectifiers 58 and 59 are poled in a direction toward a common terminal 62. Across vertical terminals 83 and 84 is directly applied the carrier generator 35, while across the horizontal terminals 61 and 82 is directly connected the signal source 38. Coupled with the inductance 68 of each network arm is an inductance 85 such that the several inductances 85 are applied in series with the load- 34. Thus, the associated inductances 88 and 85 of each netnetwork 85.

conductive and non-conductive directions. The operation of the network 18 is well understood to produce signal modulated carrier waves. The transformer windings 15 and 88 and 18 and 8| prevent direct transmission between the network 18 and the respective signaling source 38 and carrier generator 35 and the load circuit 34.

Fig. 14. shows a bridge network 85 embodying a plurality of rectifiers 83 poled in a clockwise direction. Across vertical terminals 81 and 88 is a split transformer winding 89, and across horizontal terminals 88 and 9| is a split transformer winding 92, both split transformer windings 89 and 92 and the network 85 being balanced to a relatively high degree of precision in both conductive and non-conductive directions To the mid-points of the split windings 89 and 92 is applied the load circuit 34. A split transformer winding 93 couples the carrier generator 35 to the split transformer winding 89 and thereby to the horizontal diagonal of the A split transformer winding 94 couples the signal source 38 to the split transformer winding 92 and thereby to the horizontal diagonal of the network 85. Fig. 14 operates in the well-known manner to produce signal modulated carrier waves. The transformer windings 89 and 93 and 92 and 94 prevent efiective direct transmission between the network 85 and the respective signaling source 38 and carrier generator 35.

Fig. 15 shows a bridge network 84 embodying rectifiers 95 and 98 connected alternately in series with split transformer windings 91 and 98 across whose mid-points are applied in series carrier generator 35 and signaling source 38. The

work arm prevents effectively direct transmisrectifiers 95 and 98 are poled in the same conductive direction in the network 84, and are balanced with the windings 91 and 98 to a relatively high degree of precision in both conductive and non-conductive directions. Transformer windings 99 and 188 in series couple the network 84 to the load circuit 34. Fig. 15 operates in the well-known manner to produce signal modulated carrier waves. The transformer windings 91 and 99 and 98 and I88 prevent effective direct transmission between the network 84 and the load circuit 34.

Fig. 16 is similar to Figs. 1 and 7 except an inductance I84 is disposed in series with each rectifier of each pair of parallel rectifiers- Inductances I individual to each network inductance I04 are arranged in a series-aiding relationship to couple the load 34 to network I06. Thus, the inductances I04 and I05 of each network arm prevent efiective direct transmission between the network I06 and the load circuit 34.

Although a biasing battery is not shown in any of the above embodiments of the invention, it is to be understood that suitable biasing arrangements may be included therein, when desired, in the'manner disclosed in the patents of F. A. Cowan and R. 0. Wise, 1,959,459 and 2,233,860, granted May 22, 1934, and March 4, 1941, respectively. For simplicity, all filters are omitted, but it is to be also understood that they may be used whenever required.

What is claimed is:

1. A frequency translating system comprising a bridge network comprising an inductance in at least two arms and rectifying means in at least two other arms, said rectifying means comprising a pair of rectifiers disposed in each of said two other arms, each rectifier pair comprising two rectifiers arranged in parallel and in opposite conductive directions, said inductances and rectifiers being arranged in a balanced relation, a pair of circuits for supplying alternating current waves to said network to be translated, a load circuit for utilizing the translated waves, and circuit means to connect effectively said supplying circuits and said load circuit to diagonals of said network, said circuit connecting means including a pair of further inductances coupled to said network inductances to prevent effectivelydirect transmission between said network and at least one of said supplying circuits.

2. A frequency translating system comprising a bridge network comprising a split transformer winding having one winding connected in each of two adjacent arms, rectifying means connected in each of two other adjacent arms, said rectifying means comprising a pair of non-linear rectifiers in each of said two adjacent arms, each rectifier pair comprising two rectifiers connected in parallel and oppositely disposed such that the conducting interval of one rectifier is substantially coincident with the non-conducting interval of the other, said split winding and said rectifying means being arranged in a balanced relation, a pair of circuits for supplying alternating current waves to said network to be translated, a load circuit for utilizing the translated waves, and circuit means for eflectively connecting said supplying circuits and said load circuit to diagonals of said network, said circuit connecting means including one split transformer winding coupled to said network transformer winding and effective to prevent direct transmission between said network and atleast one of said supplying circuits.

3. A modulating system comprising a non-lin- I of carrier waves, a load circuit, and circuit means for effectively connecting said signaling source, said carrier generator and said load circuit to diagonals of said network, said connecting means including a further split transformer winding ap plied to said signaling source and coupled to said network winding to prevent direct transmission between said network and said signaling source.

4. A modulating system comprising a non-linear bridge network comprising a split trans former winding having one winding in-each of two adjacent arms and non-linear rectifying means in each of two other adjacent arms, said rectifying means comprising a pair of non-linear rectiflers in each or said two other adjacent arms, each rectifier pair comprising two rectifiers connected in parallel and oppositely disposed such that the conducting interval of one rectifier is substantially coincident with the non-conducting interval of the other, said network winding and said rectifying means being arranged in a balanced relation, a source of signaling waves, a generator of carrier waves, a load circuit, and circuit means for effectively connecting said signaling source, said carrier generator and said load circuit to the diagonals of said network, said connecting means including a further split transformeriwinding'applied to said carrier generator and coupled to said network winding to prevent direct transmission between said network and said carrier generator.

RAYMOND O. WISE. 

